Obsidian Bases Skill

This skill enables skills-compatible agents to create and edit valid Obsidian Bases (.base files) including views, filters, formulas, and all related configurations.

Overview

Obsidian Bases are YAML-based files that define dynamic views of notes in an Obsidian vault. A Base file can contain multiple views, global filters, formulas, property configurations, and custom summaries.

File Format

Base files use the .base extension and contain valid YAML. They can also be embedded in Markdown code blocks.

Complete Schema

# Global filters apply to ALL views in the base
filters:
  # Can be a single filter string
  # OR a recursive filter object with and/or/not
  and: []
  or: []
  not: []
 
# Define formula properties that can be used across all views
formulas:
  formula_name: 'expression'
 
# Configure display names and settings for properties
properties:
  property_name:
    displayName: "Display Name"
  formula.formula_name:
    displayName: "Formula Display Name"
  file.ext:
    displayName

Filter Syntax

Filters narrow down results. They can be applied globally or per-view.

Filter Structure

# Single filter
filters: 'status == "done"'
 
# AND - all conditions must be true
filters:
  and:
    - 'status == "done"'
    - 'priority > 3'
 
# OR - any condition can be true
filters:
  or:
    - 'file.hasTag("book")'
    - 'file.hasTag("article")'
 
# NOT - exclude matching items
filters

Filter Operators

Operator	Description
`==`	equals
`!=`	not equal
`>`	greater than
`<`	less than
`>=`	greater than or equal
`<=`	less than or equal
`&&`

Properties

Three Types of Properties

Note properties - From frontmatter: note.author or just author
File properties - File metadata: file.name, file.mtime, etc.
Formula properties - Computed values: formula.my_formula

File Properties Reference

Property	Type	Description
`file.name`	String	File name
`file.basename`	String	File name without extension
`file.path`	String	Full path to file
`file.folder`	String	Parent folder path
`file.ext`	String

The `this` Keyword

In main content area: refers to the base file itself
When embedded: refers to the embedding file
In sidebar: refers to the active file in main content

Formula Syntax

Formulas compute values from properties. Defined in the formulas section.

formulas:
  # Simple arithmetic
  total: "price * quantity"
 
  # Conditional logic
  status_icon: 'if(done, "✅", "⏳")'
 
  # String formatting
  formatted_price: 'if(price, price.toFixed(2) + " dollars")'
 
  # Date formatting
  created: 'file.ctime.format("YYYY-MM-DD")'
 
  # Calculate days since created (use .days for Duration)
  days_old: '(now() - file.ctime).days'
 
  # Calculate days until due date

Functions Reference

Global Functions

Function	Signature	Description
`date()`	`date(string): date`	Parse string to date. Format: `YYYY-MM-DD HH:mm:ss`
`duration()`	`duration(string): duration`	Parse duration string
`now()`	`now(): date`	Current date and time
`today()`

Any Type Functions

Function	Signature	Description
`isTruthy()`	`any.isTruthy(): boolean`	Coerce to boolean
`isType()`	`any.isType(type): boolean`	Check type
`toString()`	`any.toString(): string`	Convert to string

Date Functions & Fields

Fields: date.year, date.month, date.day, date.hour, date.minute, date.second, date.millisecond

Function	Signature	Description
`date()`	`date.date(): date`	Remove time portion
`format()`	`date.format(string): string`	Format with Moment.js pattern
`time()`	`date.time(): string`	Get time as string
`relative()`	`date.relative(): string`

Duration Type

When subtracting two dates, the result is a Duration type (not a number). Duration has its own properties and methods.

Duration Fields:

Field	Type	Description
`duration.days`	Number	Total days in duration
`duration.hours`	Number	Total hours in duration
`duration.minutes`	Number	Total minutes in duration
`duration.seconds`	Number	Total seconds in duration
`duration.milliseconds`	Number

IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. You must access a numeric field first (like .days), then apply number functions.

# CORRECT: Calculate days between dates
"(date(due_date) - today()).days"                    # Returns number of days
"(now() - file.ctime).days"                          # Days since created
 
# CORRECT: Round the numeric result if needed
"(date(due_date) - today()).days.round(0)"           # Rounded days
"(now() - file.ctime).hours.round(0)"                # Rounded hours
 
# WRONG - will cause error:
# "((date(due) - today()) / 86400000).round(0)"      # Duration doesn't support division then round

Date Arithmetic

# Duration units: y/year/years, M/month/months, d/day/days,
#                 w/week/weeks, h/hour/hours, m/minute/minutes, s/second/seconds
 
# Add/subtract durations
"date + \"1M\""           # Add 1 month
"date - \"2h\""           # Subtract 2 hours
"now() + \"1 day\""       # Tomorrow
"today() + \"7d\""        # A week from today

String Functions

Field: string.length

Function	Signature	Description
`contains()`	`string.contains(value): boolean`	Check substring
`containsAll()`	`string.containsAll(...values): boolean`	All substrings present
`containsAny()`	`string.containsAny(...values): boolean`	Any substring present
`startsWith()`

Number Functions

Function	Signature	Description
`abs()`	`number.abs(): number`	Absolute value
`ceil()`	`number.ceil(): number`	Round up
`floor()`	`number.floor(): number`	Round down
`round()`	`number.round(digits?): number`

List Functions

Field: list.length

Function	Signature	Description
`contains()`	`list.contains(value): boolean`	Element exists
`containsAll()`	`list.containsAll(...values): boolean`	All elements exist
`containsAny()`	`list.containsAny(...values): boolean`	Any element exists
`filter()`	`list.filter(expression): list`

File Functions

Function	Signature	Description
`asLink()`	`file.asLink(display?): Link`	Convert to link
`hasLink()`	`file.hasLink(otherFile): boolean`	Has link to file
`hasTag()`	`file.hasTag(...tags): boolean`	Has any of the tags
`hasProperty()`	`file.hasProperty(name): boolean`

Link Functions

Function	Signature	Description
`asFile()`	`link.asFile(): file`	Get file object
`linksTo()`	`link.linksTo(file): boolean`	Links to file

Object Functions

Function	Signature	Description
`isEmpty()`	`object.isEmpty(): boolean`	No properties
`keys()`	`object.keys(): list`	List of keys
`values()`	`object.values(): list`	List of values

Regular Expression Functions

Function	Signature	Description
`matches()`	`regexp.matches(string): boolean`	Test if matches

View Types

Table View

views:
  - type: table
    name: "My Table"
    order:
      - file.name
      - status
      - due_date
    summaries:
      price: Sum
      count: Average

Cards View

views:
  - type: cards
    name: "Gallery"
    order:
      - file.name
      - cover_image
      - description

List View

views:
  - type: list
    name: "Simple List"
    order:
      - file.name
      - status

Map View

Requires latitude/longitude properties and the Maps community plugin.

views:
  - type: map
    name: "Locations"
    # Map-specific settings for lat/lng properties

Default Summary Formulas

Name	Input Type	Description
`Average`	Number	Mathematical mean
`Min`	Number	Smallest number
`Max`	Number	Largest number
`Sum`	Number	Sum of all numbers
`Range`	Number	Max - Min

Complete Examples

Task Tracker Base

filters:
  and:
    - file.hasTag("task")
    - 'file.ext == "md"'
 
formulas:
  days_until_due: 'if(due, (date(due) - today()).days, "")'
  is_overdue: 'if(due, date(due) < today() && status != "done", false)'
  priority_label: 'if(priority == 1, "🔴 High", if(priority == 2, "🟡 Medium", "🟢 Low"))'
 
properties:

Reading List Base

filters:
  or:
    - file.hasTag("book")
    - file.hasTag("article")
 
formulas:
  reading_time: 'if(pages, (pages * 2).toString() + " min", "")'
  status_icon: 'if(status == "reading", "📖", if(status == "done", "✅", "📚"))'
  year_read: 'if(finished_date, date(finished_date).year, "")'
 
properties:
  author

Project Notes Base

filters:
  and:
    - file.inFolder("Projects")
    - 'file.ext == "md"'
 
formulas:
  last_updated: 'file.mtime.relative()'
  link_count: 'file.links.length'
 
summaries:
  avgLinks: 'values.filter(value.isType("number")).mean().round(1)'
 
properties:
  formula.last_updated

Daily Notes Index

filters:
  and:
    - file.inFolder("Daily Notes")
    - '/^\d{4}-\d{2}-\d{2}$/.matches(file.basename)'
 
formulas:
  word_estimate: '(file.size / 5).round(0)'
  day_of_week: 'date(file.basename).format("dddd")'
 
properties:
  formula.day_of_week:
    displayName: "Day"
  formula.word_estimate:
    displayName

Embedding Bases

Embed in Markdown files:

![[MyBase.base]]
 
<!-- Specific view -->
![[MyBase.base#View Name]]

YAML Quoting Rules

Use single quotes for formulas containing double quotes: 'if(done, "Yes", "No")'
Use double quotes for simple strings: "My View Name"
Escape nested quotes properly in complex expressions

Common Patterns

Filter by Tag

filters:
  and:
    - file.hasTag("project")

Filter by Folder

filters:
  and:
    - file.inFolder("Notes")

Filter by Date Range

filters:
  and:
    - 'file.mtime > now() - "7d"'

Filter by Property Value

filters:
  and:
    - 'status == "active"'
    - 'priority >= 3'

Combine Multiple Conditions

filters:
  or:
    - and:
        - file.hasTag("important")
        - 'status != "done"'
    - and:
        - 'priority == 1'
        - 'due != ""'

obsidian-bases

CLI Install

Skill Instructions

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